An ordinary casing of an electronic device such as a mobile phone or a smartphone is formed into a flat shape by combining a front casing with a rear casing that are each made of a synthetic resin. More specifically, there is fixed onto a front surface of the front casing by fusion bonding or the like a protective panel that protects a liquid crystal display window. Conventionally employed as the protective panel had been a transparent and colorless resin panel. However, as disclosed in Japanese Unexamined Patent Publication No. 2001-318612, such a panel is now decorated with a printed frame or the like in accordance with the desire for a more fashionable electronic device.
In recent years, a mobile phone of a next interface has been expected to have the protective panel that also functions as an input device. Such a function as an input device may be realized by an analog resistive touch panel, and a mobile phone provided with a touch panel is exemplarily disclosed in Japanese Unexamined Patent Publication No. 2000-270063 and the like.    Patent Document 1: Japanese Unexamined Patent Publication No. 2000-270063    Patent Document 2: Japanese Unexamined Patent Publication No. 2001-318612